Healthcare Action Engine Settings

The Settings page contains additional items necessary for your CDS Hooks services, along with advanced customization options. To access the settings page, select Settings from the drop-down user menu in the header bar of the InterSystems® Healthcare Action Engine configuration application.

Your required configuration items consist of:

Adding the proper URIs to the CDS Hooks and Cross-Origin allow lists so that your client application’s API requests are handled properly.

Allow Lists

You can edit two categories of allow lists on this page:

CDS Hooks Allow List — Per the CDS Hooks specification (see https://cds-hooks.hl7.org/2.0/#trusting-cds-clientsOpens in a new tab), HAE only validates a request’s bearer token when it finds the value of the token’s jku header (which specifies the JWK Set URL containing the client’s public keys) and iss field (which specifies the URI for the token’s issuer) on its internal lists of allowed values. To permit a client to interact with HAE, add the client’s expected jku header to the jku Allow List and add a client’s expected token issuer to the iss Allow List.

Important:

Only known, trusted URIs should be added to these lists.
Cross-Origin Allow List — For security reasons, modern browsers follow the CORS protocolOpens in a new tab to restrict cross-origin HTTP requests initiated from web pages. These HTTP requests therefore include the “Origin” header, the value of which is the host name of the server that served the web page. It is expected that the value of the Access-Control-Allow-OriginOpens in a new tab response header is the same server host name; this tells the browser that client-side code running in the browser can access the response object. In order for the response header to contain the URI of the web page’s host server, you must add this URI to the Cross-Origin allow list.

Adding a URI to an Allow List

To add a URI to the CDS Hooks or Cross-Origin Allow List:

Go to the configuration application.
Select Settings > CDS Hooks Allow List.
Enter your URI under jku URI, iss URI, or origin URI and select Allow to save the URI.

Removing a URI from an Allow List

To remove a URI from the CDS Hooks or Cross-Origin Allow List:

Go to the configuration application.
Select Settings > CDS Hooks Allow List.
Select the checkbox next to the URI you wish to remove, and select Remove Selected URI.

Configuring Rule Inputs

A rule input specifies data that must be retrieved from the client application’s HL7® FHIR® repository to evaluate a rule.

HAE creates and maintains rule inputs when you use the HAE Rule Editor to build expressions which involve FHIR queries. In general, it is unnecessary to modify rule inputs for a rule which was created using the Rule Editor.

Important:

Modifying rule inputs is an advanced configuration procedure; improperly formed Retrieval Text may cause the Rule Editor to stop functioning for the associated rules.

To configure the properties of a rule input:

Go to the configuration application.
Select Settings > Rule Inputs.
Select the drop-down menu for whichever rule whose rule input(s) you wish to configure, and select the edit button (under Actions) next to that particular rule input.
Enter values for the following fields:
- Retrieval Text — the selector for requesting a FHIR resource (or bundle of resources). This text may contain parameters that refer to values provided by the context of the trigger that invoked a rule, for example the ID of a patient. While the rule input retrieval text is generated automatically based on the user’s selections during input creation in the Rule Editor, there may be cases that require customization.
- Description — a user-friendly text description for the resource object to be retrieved and its purpose in relation to evaluating your rule.

When an expression is deleted in the rule editor canvas, the associated rule is not deleted. You can select the trash bin icon next to the desired rule input to delete it.

Adding Code System Shortcuts

When creating expressions that involve numerical values, you may wish to specify a unit code and unit system. You can add shortcuts for these code systems to simplify rule authoring.

To add a shortcut name for a code system:

Go to the configuration application.
Select Settings > Code System Shortcuts.
To the right of the Code System Shortcuts or Unit Code System Shortcuts table, select +New Shortcut.
Enter values for the following fields:
- Clinical Code System Shortcut Name or Unit Code System Shortcut Name — a brief name to reference this code system when selecting in the Rule Editor.
- Description — a text description of this code system. This field is optional.
- URI — the URI for this code system.

Rule Functions

Note:

If you have created a demo production of Healthcare Action Engine, the Functions table will contain demo functions as examples.

A rule function is a block of logic that can be repeatedly called in your rules. A rule function can return number types (integers, numerics, booleans).

You can use a rule function in your rule by assigning the function to a variable name.

Creating a Rule Function

To create a rule function:

Create a rule. Add any FHIR queries you wish to be included in your rule function.

Important:

The FHIR package and trigger you select will not be editable once you have imported this rule in step 4.
Go to the configuration application.
Select Settings > Rule Functions.
Select + Import Rule Function and select a rule from the drop-down menu.

Important:

The rule you import will be converted to a rule function and will no longer be available as a rule. You will not be able to use the Healthcare Action Engine rule editor to update the FHIR queries in your rule function.
Select the icon to edit your rule function in the Interoperability Business Rule Editor. See here for more information about using the Business Rule Editor.
Add any logic you wish, including your desired return type.
Select Save to save your rule function.

You can now use an assign element in the Healthcare Action Engine Rule Editor to include the function in a rule.

Editing a Rule Function’s Metadata

You can edit the metadata of a rule function in the Healthcare Action Engine:

Go to the configuration application
Select Settings > Rule Functions.
Select the pencil icon (under Actions) next to the name of the rule function you wish to edit.
Update values as desired for the following fields:
- Description — a user-friendly text description for your rule function.
- Topic — a user-friendly label for your rule function.
Note:

Fields not listed above are not editable.
Select Save to save your updated rule function.

Create Rules to Evaluate Conditions Using the Rule Editor